Jacobsite
Kurokawa, Hishi village, Kiryu city, Gunma pref., Japan
Field of view: 10 mm. Jacobsite associated with rhodonite. The parallel black veins are aggregate of fine jacobsite crystals. The massive dark brown ellipsoids associated with jacobsite veins are fine aggregate of sonolite or alleghanyite. The massive white part at the left is the host chert.
Recovered from a chert-hosted bedded manganese deposit subjected to Albite-Epidote-hornfels contact metamorphism.
Jacobsite from this location was described in 2003.
Other localities
- Kurokawa Mine (Mn skarn, Band)
- Kiyokawa Mine (Bedded Mn, Zeo facies)
- Gozaisho Mine (Mn Skarn, Iwakiite)